$11\mathrm{.}13$ Identify the legally insufficient consideration

A$)$ Alex promised to pay Tom for his car in four installments of $$1,000$ each. He fails to pay these installments. Tom threatens suit, to which Alex promises to pay just $$100$ in exchange for Tom's promise to release him from the remainder of the amount

B$)$ Alex promised to pay Tom for his car in four installments of $$1,000$ each. He fails to pay these installments. Tom threatens to sue him, to which Alex promises to pay an interest of $2$ percent whenever he gets his debtors to repay him

C$)$ Alex promised to pay $$1,000$ to Tom for his car, due March $1.$ On March $1,$ Tom pays only $$400$ in exchange for Tom's promise to release him from the remainder of the amount

D$)$ Alex promised to pay $$1,000$ to Tom for his car, due March $1.$ On February $27,$ Tom pays only $$400$ in exchange for Tom's promise to release him from the remainder of the amount

E$)$ Alex promised to pay $$1,000$ to Tom for his car, due March $1.$ On March $18,$ Tom pays only $$400$ and takes Alex to the carnival